Method of forming brake shoes



METHOD OF FORMING BRAKE SHOES Filed April 22, 1955 2 Sheets-Sheet 2 23 26 I? Il www NVENTOR WALTER P. SMITH Patented July 7, 1936 PATENT oFFlcE METHOD OF VFORMINGr BRAKE SHOES Walter P. Smith, Detroit, Mich., assigner to Kelsey-Hayes Wheel Company, Detroit, Mich., a corporation voi. Delaware Application April 22, 1935, Serial No.717,718

15 Claims. (Cl. Ztl-152.1)

' This invention Yrelates generally to an improved method of forming a strip of stock 'of T-shaped cross section to van arcuate contour, and refers more particularly to method of forming brake shoes.

The usual procedure in forming brake shoes of T-shaped cross section is to introduce a vstrip of stock of corresponding cross section to a suitable rolling machine designed to fashion the strip into an arcuate section of the specified size and to maintain the stem portion of the T in a plane extending at right angles to the arcuate surface of the stock during the rolling operation. A1- though the above method has been found satisfactory insofar as the cost of manufacture of brake shoes is concerned, nevertheless, it is objectionable in that upon completion of the rolling operation, a slight depression exists in the exterior surface of the head of the T` directly opposite the stem of the latter. Notwithstanding the fact that the brake lining is applied vto the exterior surface of the head, it is extremely important that all points on this surface in transverse or radial A-planes passing through `the axis Y ofthe shoe lie in straight lines, otherwise the effective braking `area of the Vsurface is reduced and a consequent reduction in braking yefliciency results.

VThe depression inthe exterior surface of the head vof the T-shaped strip resulting from the rolling operation briefly set forth above, may be due to the fact that the Widely varyin-'gFwidt-hs of the stems of the T-sectionv Astrips render -it impractical to support ther-ree edges of the stems during the rolling operation, and vconsequently, the resistancev offered to 'bending by theV portion of the strip in theregion of the `Vstem is AdilTeren-t from that oifered by the remaining'por- 4tions of the strip. Irrespective of the cause Aof `the depression -i-n the `exterior surface Aof the shoe, the present invention contemplates the provision of a brake shoe with -a rolled exterior surface wherein alllof the points onthe sur-face lying in radi-alplfanes passing through the axis `of the l :shoe lie in `straight lines and,r as a consequence the :entire area `of the exterior surface of the lining applied to `the .shoe is effective.V

\ A further advantageous feature of the present :invention `resides in improving the 'method of rolling istrip stock yof Teshaped cross section into brake shoes so that an exterior surface Avvil'lzbe imparted to the brake shoe having -all of the kpoints in radial planes passing 4through the axis ,of the shoe lie in straight lines.. In accordance with this invention two anemanve methods may be employed for accomplishing the above results, and both of these methods Will be more fully hereinafter described in connection with the accompanying drawings, wherein:

Figure 1 is a semi-diagrammatic cross sectional view through arolling machinesuitable for forming arcuate T-shaped stock in accordance with this invention;

Figure 2 is a cross sectional View of a strip of stock employed to form a brake shoe in accordance with one embodiment of this invention;

Figures 3, 4, 5 and `6 are, respectively, cross sectional views taken on the lines 3 3, d--l 5 5 and 6--6 of Figure 1; and

Figure 7 is a cross sectional vieW ofa strip of stock employed to form a brake shoe in accordance with another embodiment of this invention.

In the embodiment of the invention illustrated in vFigures 1" .to 6 inclusive, a strip of T-section stock of the required length is introduced to a rolling machine andris rolled to an .arcuate contour. During theV rolling operation, a raised beadlis formed on the exterior suiace of the head of the T-shaped strip `directlyropposite the stemof the T and, also, this bead or raised portion is progressively ironed out as the rolling operation continues to form what may be termed an arcuate ruled exterior surface on the head of Athe T, or in other Words, to provide an arcuate surface wherein all of the points in radial planes passing through the axis of thearcuate section lie in straight lines. In general, the method of rolling is such that a greater Vrolling pressure is initially exerted upon the flanges of the T than upon the portion of the T opposite the stem during the rolling operation to form `the raised bead and the pressure exerted on the bead is graduallyincreased yas the rolling operation continues to iron out the bead. This procedure insures 'forming the exterior surface of the head of the T with all of the points on this surface lying in straight lines Aextending at right angles to the plane of the stem of the T and as previously stated, this is important in that it renders it possible to provide uniform engagement of the lining applied to the surface with the brakeflange of the drum (not shown).

In detail, I have shown diagrammatically in Figure 1 a rolling machine for accomplishing the above results and comprising a master or supporting roll Il) and a plurali-ty of cooperating for-ming rolls l l. The master roll l!) is formed of two cooperating sections l2 and |,3 having recesses I4 in the .adjacent surfaces thereof cooperating to form .a slot I5 of sufficient dimension to receive the stem portion I6 of the T-section strip II. The cooperating sections I2 and I3 are splined upon a drive shaft I8 for relative axial displacement, and are normally urged in directions toward each other through the medium of suitable hydraulically operated devices I9 capable of applying considerable pressure to the roll sections during the rolling operation in directions to rigidly clamp the stem portions of the T therebetween. The arrangement is such as to prevent buckling of the stem portions I6 during the rolling operation and it is to be understood that any suitable mechanism may be employed for accomplishing this result.

In the present instance, four forming rolls cooperate with the master roll I8 to roll the T- shaped strip I'I to an arcuate contour, and these rolls are individually designated in Figure 1 by the reference characters 2B, 2I, 22 and 23. The aforesaid forming rolls are supported in predetermines spaced relationship to cooperate with the master roll in fashioning the T-section strips and each of these rolls is secured to a shaft 24 driven from the drive shaft I8 through the medium of the gearing 25.

The periphery of each of the forming rolls II is provided with a recess 25 corresponding in width to the Width of the head of the T-section strip to receive the latter, and also adapted to receive a portion of the periphery of the master roll I0, in the manner shown in any one of Figures 3 to 6 inclusive. By reference to Figure 3, it will be noted that the working surface of the forming roll 20 is provided with an annular recess 2'I midway between the side edges thereof adapted to assume a position directly opposite the stem of the T-section, so as to roll a raised bead 28 on the exterior surface of the head 29 of the T-section opposite the stem I6. It will be observed from Figure 4, that the forming roll 2I is also provided with an annular recess 30 in the periphery thereof, similar to the recess 2'I, but slightly smaller so that as the strip passes beneath the forming roll 2| the raised bead 28 is reduced in size. The bead 28 is completely eliminated or ironed out by the forming rolls 22 and 23 shown in Figures 5 and 6 respectively, since the recesses are eliminated in these forming rolls. As a matter of fact, the working surfaces of the final rolls 22 and 23 are truly cylindrical, so that upon completion of the rolling operation the T- section will not only possess the required arcuate contour, but also all the points on the exterior surface of the head of the T in radial planes passing through the axis of the shoe will lie in straight lines. As stated above, a surface of this character may be termed a ruled arcuated surface and is desirable since it provides a uniform backing for the brake lining usually applied to the surface.

The results secured by the alternative method of forming brake shoes, shown in Figure '7, are the same as the results obtained by the method previously set forth, but the alternative method differs from the first described method in that the T-section strip 35 is fashioned to provide the raised bead 28 on the exterior surface of the head 29', prior to introducing the strip to the rolling machine, instead of during the rolling operation. This may be accomplished by forming the bead on the section during the milling operation, or by displacing the stem I 6 of the T in a direction toward the head. In either case, the raised bead is progressively ironed out in the same manner as described in connection with the first embodiment of this invention to form the rolled arcuate surface previously referred to.

Thus from the foregoing, it will be observed that I have provided a relatively simple and inexpensive method of forming brake shoes from T-section stock, distinguished in at least one respect from prior methods, in that the exterior surface of the resulting brake shoe forms a section of a truly cylindrical surface.

What I claim as my invention 1s:

1. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem, rolling the head to form an arcuate strip and ironing out the bead to form the exterior surface of the head between opposite sides thereof into a section of a truly cylindrical surface.

2. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem of the latter, and rolling the head including the bead to form an arcuate strip and to iron out the bead to form the head with an exterior surface having all of the points thereof in radial planes passing through the axis of the arcuate strip lying in straight lines.

3. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem of the latter, rolling the head including the bead to form an arcuate strip, and simultaneously ironing out the bead to impart a rolled arcuate surface to the exterior of the head.

4. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem of the latter, forming the T-section into an arcuate strip, and ironing out the bead to form the head with an exterior surface having all of the points thereof in radial planes passing through the axis of the arcuate strip lying in straight lines.

5. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem of the latter, and rolling the head including the bead to form an arcuate strip and to iron out the bead to form the head with an exterior surface having all of the points thereof in transverse planes passing through the axis of the arcuate section lying in straight lines.

6. Those steps in the method of forming a brake shoe from T-section stock which consist in rolling the head of the T to form an arcuate strip, forming a bead on the exterior surface of the head opposite the stem of the T during the rolling operation and ironing out the bead to form the head with an exterior surface having all of the points in planes perpendicular to the stem of the T lying in straight lines.

7. Those steps in the method of forming a brake shoe from T-section stock which consist in rolling the head of the T to form an arcuate strip, forming a raised bead on the exterior surface of the head of the T opposite the stern of the latter during the initial rolling operation, and ironing out the bead during the final rolling operation for the purpose set forth.

8. Those steps in the method of forming a brake shoe from T-section stock which consist in rolling the head of the T to simultaneously form an arcuate strip and to successively form a bead on the exter'ior surface of the head opposite the stem and iron out the bead to forrnthe head with an exterior surface having all of the points thereof in transverse planes passing through the axis of the arcuate surface lying in straight lines.

9. Those steps in the method of forming a brake shoe from T-section stock which consist in forming a raised bead on the head of the T opposite the stem of the latter, rolling the head including the bead to form an arcuate strip and. to iron out the bead to impart a ruled arcuate surface to the` exterior of the head, and exerting pressures on opposite sides of the stem of the T during the rolling operation to hold the stem from buckling.

10. Those steps in the method of forming a brake shoe which consist in prefashioning T-section stock to form a raised bead on the exterior surface of the head of the T opposite the stem of the latter, rolling the head to form an' arcuate strip and ironing out the bead to form the head with an exterior surface having all of the points thereof in transverse planes passing through the axis of the arcuate strip lying in straight lines.

11. Those steps in the method of forming a brake shoe which consist in prefashioning T-section stock to form a raised bead on the exterior surface of the head of the T opposite the stem of the latter, rolling the head to form an arcuate strip and ironing out the bead during the rolling operation to form the head with an exterior surface having all of the points in transverse planes passing through the axis of the arcuate strip lying in straight lines.

l2. Those steps in the method of forming a brake shoe which consist in prefashioning T-section stock to form a raised bead on the exterior surface of the head of the T opposite the stem of the latter, rolling the head to bend the stock to an arcuate contour, and ironing out the bead by the bending rolls to form the head with an exterior surface having all of the points thereof in transverse planes passing through the axis of the arcuate strip lying in straight lines.

13. Those steps in the method of forming a brake shoe from T-section stock Which consist in forming a raised bead on the head of the T opposite the stem of the latter, rolling the head including the bead to bend the stock to an arcuate contour, ironing out the bead by the bending rolls to impart a ruled arcuate surface to the exterior of the head of the T, and holding the stem of the T from buckling during the rolling operation.

14. Those steps in the method of forming stock having a web and having a head extending transversely of the web which consist in forming a raised bead on the head opposite the web, hooping the stock to form an arcuate strip, and ironing out the bead to form the exterior face of the head into a section of a true cylindrical surface.

15. Those steps in the method of forming stock having a Web and having a head extending transversely of the Web which consist in rolling the head to form the stock into an arcuate strip and to form the portion of the head opposite the web of greater thickness than the remaining portion of the head, and ironing the bead to form the exterior face of the head into a section of a true cylindrical surface.

WALTER P. SMITH.

CRTIFICAT OF CORRECTION.

Patent No. 2,047,084. July '7, 1936.

WALTER P. SMITH.

It is` hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 35, claim 3, for the word "rolled" read ruled; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the oase in the Patent Office.

Signed and sealed this 23rd day of February, A. D. 1957.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

